c# - 2 个 GroupJoin 在一个查询中

Question

我有一个这样的查询，它将两个实体连接在一起：

IEnumerable<ICD.ViewModels.HomeSearchViewModel> query =
ICDUnitOfWork.AlphaGroups.Find().GroupJoin(ICDUnitOfWork.Alphas.Find(),
                                           a => a.AlphaGroupID,
                                           g => g.AlphaGroupID,
                                           (alphaGroups, alphas) =>
                                           new ICD.ViewModels.HomeSearchViewModel
                                           {
                                               AlphaGroups =
                                                   alphaGroups,
                                               Alphas = alphas,
                                               SearchTerm = searchTerm
                                           }).OrderBy(x => x.AlphaGroups.Title);

我需要将 Alphas 实体与另一个名为“代码”的实体连接起来。是否可以在单个查询中执行此操作，还是应该将其分解为 2 个单独的查询？

Answer 1

标准实体框架查询看起来更像：

var query =
  from a in dbContext.Alphas
  from g in a.AlphaGroups
  from c in a.Codes
  select new {Alpha = a, AlphaGroup = g, Code = c}

也许：

var query =
  dbContext.Alphas.Include("AlphaGroups").Include("Codes");

为什么您的查询看起来如此糟糕？